2005 OCTOBER 19: CAMP HOUSTON, OK SUPERCELL AND TORNADO

                      
(looking south)
The condensation tendrils we observed beneath the mesocyclone were difficult to discern, and as a result I turned my camera
on a few seconds too late to capture the best of them.  Further obscuring the imagery is the rain both behind the circulation
(to the south) and mixing in among it.  These narrow rain curtains---separate from the condensation vortices---moved from
the main precip core into the circulation and then shot off to the east rapidly.  I've never seen anything like it and have no explanation. 
As for the vortices, Eric and I were convinced of ground circulation at the time and after reviewing the video remain so.  Unfortunately,
because of the surprise nature of the event and our location, these are the best grabs I could extract from my video.  By the way,
the third image above was reported by some chasers as a wedge tornado.  It wasn't.  It was simply a large area of rain that descended
rapidly from the southern region of the hook.

 

Short Version:

Eric Nguyen and I observed a tornado south of State Highway 64 near Camp Houston, Oklahoma about 2332z. Coming from behind the storm, we emerged with the mesocyclone still south of the road and rotating violently. The storm exhibited a sharply striated updraft and the radar presentation, from saved imagery we saw later, was remarkable given the early mode of all convection in the area. The tornado formed due south of our position and caught us by surprise as the primary rotation was more to the east southeast. We had stopped to photograph and film the rotation and noticed a condensation funnel halfway to the ground to our south. Within moments, this rotation tightened and narrow vortices descended to the ground. Several of these condensation tendrils rotated around the main circulation, with mist and rain caught in between. The tornado lasted about five minutes and occluded before reaching the road. I phoned OUN and reported the event.


Long version:

Our target was around and west of Woodward where we expected a triple point to move from the eastern and northeastern Texas panhandle. We believed storms could fire on the dryline and remain isolated, but it seemed likely that higher dewpoint depressions and the lack of an identifiable boundary would mitigate tornado chances. In northwest Oklahoma, we felt a storm could fire and move near the boundary, and perhaps take advantage of higher RH air and enhanced helicities along or just north of the baroclinic boundary. With consistent MLCAPE forecasts around ~2000 j/kg (with the exception of the 15z and 18z RUC which overestimated the coverage of morning/early afternoon precip), an aggressively mixing dryline, and some moisture pooling south of a stalled front, we thought there was a small chance for tornadoes.

Convection fired in the northeast Texas panhandle and split repeatedly as suggested by earlier posts regarding the straight line hodos. Our 850mb winds were slow to back and we wondered if this evolution would be rule of the day. However, a cell in northern Ellis County anchored on an outflow boundary that lay southwest to northeast (we’d earlier observed this as a thin line of cu on visible satellite stretching more or less along Highway 15 at 19z) and stopped moving. We were north of Laverne at the time, having pursued and abandoned cells destined for southern Kansas. After one last split, the northern updraft exhibited a small funnel below the rain free base and a midlevel funnel. The southern split intensified and we dropped south to position ourselves. We hoped that backing 850 winds and vorticity advection from the approaching trough had improved the synoptic environment for the ongoing convection.

We observed a few lowerings and modestly rotating wall clouds until the storm accelerated and we lost position, finding ourselves west and then northwest of the updraft. We shot north and then east on 64, entering the backside of the storm around the Cimarron River.

In the Bear’s Cage, rain wrapped around the hook and we observed the rotation I mentioned before. Another interesting feature of this tornadic circulation was a small area of intense precipitation that preceded it. This small core of rain looked “driven” or forced downward and we later wondered if this was something similar to Dr. Rasmussen’s descending reflectivity cores or “blobs.” As the circulation tightened, it filled with dirt, mist, and these intense, carouseling condensation tendrils that reminded me of the October 9, 2001 vortices beneath the Mountain View tornado before it became a large cone.

A very satisfying and somewhat surprising October chase as storms developed both remarkable structure and tornadoes within chaseable daylight.

  

  

 

 

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